Vacuum suction unit

ABSTRACT

A vacuum suction unit is provided. The vacuum suction unit includes a cover, an impeller, a motor, a guide device which includes a guide body and a guide vane, a flow guide which is disposed below the guide device and guides the air guided by the guide device toward the stator, and a motor housing which accommodates the motor and includes an air outlet. Here, a guide surface at least a part of which has a diameter reduced as getting downward is formed at a bottom surface of the flow guide, the guide vane includes a first guide vane which is provided on a side of the guide body and guides the air ejected from the impeller, and an inlet angle of the first guide vane is within a range from 10 to 25 degrees.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority under 35 U.S.C. 119 and 35U.S.C. 365 to Korean Patent Application No. 10-2015-0045951 (filed onApr. 1, 2015) and No. 10-2015-0048234 (filed on Apr. 6, 2015), which arehereby incorporated by reference in their entirety.

BACKGROUND

A vacuum suction unit may be generally included in an electric cleanerand used to suction in air including dust.

Korean Patent Publication No. 2013-0091841 (Aug. 20, 2013) which is aprior document discloses a vacuum suction unit.

The vacuum suction unit includes a motor, an impeller connected to amotor by a rotating shaft and suctioning in air by rotating, a guidemember adjacently disposed to the impeller and guiding air ejected bythe impeller, and a cover which covers the impeller and the guidemember.

The guide member includes a body portion disposed below the impeller anda guide vane which is formed on a side of the body portion and guidesthe air ejected by the impeller. An air flow path through which airflows is formed between the cover and the body portion. The air whichflows into inside the cover due to the impeller passes through the airflow path and moves toward the guide vane.

The vacuum suction unit of the prior document has a large flow lossduring a process in which the air ejected by the impeller is guided bythe guide vane.

Also, a vortex may occur during a process in which the air which flowsin due to the impeller flows through the air flow path, therebygenerating a flow loss.

SUMMARY

An aspect of the present invention provides a vacuum suction unit whichminimizes a flow loss by optimizing an inlet angle of a guide vane andan angle of inclination of a flow guide.

Another aspect of the present invention provides a vacuum suction unitwhich reduces a flow loss by optimizing a shape of an air flow path.

According to one aspect of the present invention, a vacuum suction unitincludes a cover which includes an air inlet, an impeller for moving airwhich flows in through the air inlet, a motor which includes a statorand a shaft which is connected to the impeller and rotates with respectto the stator, a guide device which includes a guide body disposed belowthe impeller and a guide vane provided at the guide body to guide airejected from an outlet of the impeller, a flow guide which is disposedbelow the guide device and guides the air guided by the guide devicetoward the stator, and a motor housing which accommodates the motor andincludes an air outlet. Here, a guide surface at least a part of whichhas a diameter reduced as getting downward is formed at a bottom surfaceof the flow guide, the guide vane includes a first guide vane which isprovided on a side of the guide body and guides the air ejected from theimpeller, and an inlet angle of the first guide vane is within a rangefrom 10 to 25 degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the followingdrawings in which like reference numerals refer to like elements, andwherein:

FIG. 1 is a front view of a vacuum suction unit according to oneembodiment of the present invention;

FIG. 2 is an exploded perspective view of the vacuum suction unit ofFIG. 1;

FIG. 3 is a longitudinal cross-sectional view of the vacuum suction unitof FIG. 1;

FIG. 4 is a view of a guide vane according to one embodiment of thepresent invention;

FIG. 5 is a graph illustrating efficiency depending on an inlet angle ofa guide vane;

FIG. 6 is a bottom view of a flow guide shown in FIG. 2;

FIG. 7 is a view illustrating an angle between the flow guide and ahorizontal line;

FIG. 8A is a cross-sectional view of a conventional vacuum suction unit;

FIG. 8B is a cross-sectional view of the vacuum suction unit accordingto one embodiment of the present invention;

FIG. 9A illustrates an airflow of the conventional vacuum suction unit;

FIG. 9B illustrates an airflow of the vacuum suction unit according toone embodiment of the present invention; and

FIG. 10 illustrates graphs about efficiency of the conventional vacuumsuction unit shown in FIG. 8A and the vacuum suction unit according toone embodiment of the present invention shown in FIG. 8B.

DETAILED DESCRIPTION

FIG. 1 is a front view of a vacuum suction unit according to oneembodiment of the present invention. FIG. 2 is an exploded perspectiveview of the vacuum suction unit of FIG. 1. FIG. 3 is a longitudinalcross-sectional view of the vacuum suction unit of FIG. 1.

Referring to FIGS. 1 to 3, a vacuum suction unit 1 according to oneembodiment of the present invention may include a cover 10 whichincludes an air inlet 102 and a motor housing 60 which includes one ormore air outlets 602.

The cover 10 may guide air which flows in through the air inlet 102toward an impeller 20. Also, the cover 10 may maintain a vacuum pressureby insulating inner space from outside air pressure.

The vacuum suction unit 1 further includes the impeller 20 accommodatedin the cover 10.

The impeller 20 increases static pressure energy and dynamic pressureenergy of the air which flows in through the air inlet 102. Accordingly,a flow rate of the air may be increased by the impeller 20.

The impeller 20, for example, may include a hub 210 and a plurality ofimpeller blades 212 arranged in the hub 210.

Each of the impeller blades 212 may extend from a top end 213 a to abottom end 213 b and may be formed in a three-dimensional shape. The airwhich flows may be moved to spaces between each of the adjacent impellerblades 212. Accordingly, spaces between the bottom ends 213 b of theplurality of impeller blades 212 may be referred to as impeller outlets214.

The air which flows in through the air inlet 102 may flow in through atop end of each of the impeller blades 212 and may be radially guidedtoward the bottom end 213 b of each of the impeller blades 212.

The vacuum suction unit 1 may further include a guide device 30 whichguides a flow of the air discharged through the impeller outlet 214.

The guide device 30 converts the dynamic pressure energy of the energycomponents of the air discharged through the impeller outlet 214 intothe static pressure energy. That is, the guide device 30 may increasestatic pressure energy by reducing a flow rate of a fluid.

At least a part of the guide device 30 may be located in the cover 10,and the impeller 20 may be located above the guide device 30.

The guide device 30 may include a guide body 310 and a plurality ofguide vanes 330 arranged around the guide body 310.

For example, the guide body 310 may be formed in a cylindrical shape,and the plurality of guide vanes 330 may be arranged along acircumferential direction of the guide body 310 with each spaced apart.

The guide vanes 330 may include a first guide vane 331 provided on aside of the guide body 310 and a second guide vane 332 which extendsfrom the first guide vane 331 and is provided at a bottom surface of theguide body 310.

The first guide vane 331 may vertically extend, and the second guidevane 332 may horizontally extend. The second guide vane 332 is disposedon the bottom surface of the guide body 310, thereby increasing a lengthover which the flow of the air is guided.

The first guide vane 331 may be located over a first flow path P1 and asecond flow path P2 which will be described below. The second guide vane332 may be located at the second flow path P2.

The vacuum suction unit 1 may further include a motor bracket 40 to becoupled with the cover 10.

The motor bracket 40 may include a bracket body 402, a supporter 404disposed in an inner portion of the bracket body 402, and a connectionportion 406 which connects the bracket body 402 with the supporter 404.

The motor bracket 40 may be disposed between the cover 10 and the motorhousing 60 and may be fastened to each of the cover 10 and the motorhousing 60. For example, the motor bracket 40 may be fastened to abottom of the cover 10, and the motor housing 60 may be coupled with abottom of the motor bracket 40.

The cover 10 may include a first coupling portion 114 to be connectedwith the motor bracket 40. The first coupling portion 114, as shown inthe drawing, may be formed in an annular shape.

The motor bracket 40 may include a second coupling portion 410 to beconnected with the first coupling portion 114. The second couplingportion 410 may be provided outside the bracket body 402.

A bottom surface of the first coupling portion 114 is in contact with atop surface of the second coupling portion 410. A plane which is formedby connecting points where the bottom surface of the first couplingportion 114 meets the top surface of the second coupling portion 410 isreferred to as a parting line PL. Since the parting line PL is a placewhere the cover 10 and the motor bracket 40 are connected and an airleak may occur, the bottom surface of the first coupling portion 114 andthe top surface of the second coupling portion 410 are formed in shapescorresponding to each other.

One part of the motor bracket 40 may be located on sides of theplurality of guide vanes 330, and another part thereof may be locatedbelow the plurality of guide vanes 330.

The parting line PL is disposed lower than top end portions 334 of eachof the guide vanes 330.

Accordingly, the air which flows through the first flow path P1 arrivesat inlets of the plurality of guide vanes 330 and is guided beforearriving at the parting line PL.

A position of the parting line PL is disposed below the inlets 314 ofthe plurality of guide vanes 330 as described above, thereby reducing aflow loss of the air.

The supporter 404 may support the guide device 30. In detail, the guidebody 310 may be mounted on the supporter 404. A part of the supporter404 may be accommodated in the guide body 310.

To prevent the supporter 404 from acting as a resistance to the airguided by the second guide vane 332, the supporter 404 may be locatedhigher than a bottom surface of the second guide vane 332.

With the guide body 310 mounted on the supporter 404, an outer side ofthe guide body 310 may be spaced apart from an inner side of the cover10. Accordingly, the first flow path P1 for allowing the air to flow maybe formed between the outer side of the guide body 310 and the innerside of the cover 10.

With the guide body 310 mounted on the supporter 404, the outer side ofthe guide body 310 may be spaced apart from the bracket body 402.Accordingly, the second flow path P2 for allowing the air to flow may beformed between the outer side of the guide body 310 and the bracket body402.

The second flow path P2 is connected with the first flow path P1. Aboundary between the first flow path P1 and the second flow path P2corresponds to a virtual plane formed by connecting points where thebracket body 402 and the cover 10 meet.

At least a part of the guide body 310 may be disposed between thesupporter 404 and the bracket body 402 while mounted on the supporter404. That is, at least a part of the guide device 30 may be accommodatedin the motor bracket 40.

The guide body 310 may further include a rim portion 316 provided on anouter circumference.

The rim portion 316 may be provided outside the impeller 20.Accordingly, the air discharged through the impeller outlet 214 of theimpeller 20 flows toward a top of the rim portion 316.

An inner circumferential surface 110 of the cover 10 may incline withrespect to a top surface portion 317 of the rim portion 316 at apredetermined angle θ. The predetermined angle θ means an angle formedby an extension line L1 of the inner circumferential surface 110 of thecover 10 and a horizontal line HL.

The first flow path P1 may become narrower toward the top end portion334 of the guide vane 330. In other words, the first flow path P1 maybecome narrower in a direction the air moves.

Also, a shape of the inner circumferential surface 110 of the cover 10may be streamlined as shown in the drawing. This is to minimize airresistance and to prevent a vortex of air. Accordingly, the flow loss ofthe air which flows through the first flow path P1 may be reduced.

The plurality of guide vanes 330 may be located over the first flow pathP1 and the second flow path P2 and may guide the flow of air.

One or more of the plurality of guide vanes 330 may be in contact withthe bracket body 402 while the guide body 310 is mounted on thesupporter 404.

The vacuum suction unit 1 may further include a motor for rotating theimpeller 20.

The motor may be accommodated in the motor housing 60. Accordingly, themotor may be located below the supporter 404.

The motor may include a stator 80, a rotor which rotates with respect tothe stator 80, and a shaft 72 connected to the rotor 70.

The stator 80 may include a coil 802. Although not limiting, the rotor70 may be located inside the stator 80. The rotor 70 may include apermanent magnet.

One or more bearings 74 and 76 may be coupled with the shaft 72. The oneor more bearings 74 and 76 may include an upper bearing 74 and a lowerbearing 76. The upper bearing 74 may be located at an upper portion ofthe rotor 70, and the lower bearing 74 may be located at a lower portionof the rotor 70.

The upper bearing 74 may be supported by the supporter 404 of the motorbracket 40. For example, at least a part of the upper bearing 74 may beaccommodated in the supporter 404. Although not limiting, the upperbearing 74 may be inserted into the supporter 404 from a bottom portionof the supporter 404.

The motor housing 60 may support the lower bearing 76.

The vacuum suction unit 1 may further include a flow guide 50 whichguides the air guided by the guide vane 330 toward the stator 80.

The flow guide 50 may be fastened to the supporter 404 of the motorbracket 40 by a first fastening member S1. Also, the guide device 30 maybe fastened to the supporter 404 by a second fastening member S2.

At least a part of the supporter 404 may be inserted into the flow guide50.

To prevent interference in the connection portion 406, the flow guide 50may include an opening 502 through which the connection portion 406passes.

The shaft 72 may pass through the motor bracket 40 and the guide device30 and may be coupled with the impeller 20. For example, the shaft 72may pass through the supporter 404 and the guide body 310.

The airflow in the vacuum suction unit 1 will be briefly describedbelow.

When power is applied to the vacuum suction unit 1, the motor is driven.Then, the rotor 70 rotates from the stator 80, and the shaft 72 coupledwith the rotor 70 is rotated. When the shaft 72 is rotated, the impeller20 connected to the shaft 72 is rotated.

Due to the impeller 20, air outside the vacuum suction unit 1 flows intothe cover 10 through the air inlet 102. The air which flows into thecover 10 moves along the impeller 20.

The air discharged through the impeller outlet 214 is guided by thecover 10 to flow toward the guide vane 330 of the guide device 30. Afterthat, the air flows along the first flow path P1 and the second flowpath P2 during which the guide vane 330 guides the flow of the air.

The flow direction of air which passes through the second flow path P2is changed by the flow guide 50 and flows downward. A part of the airwhich passes through the second flow path P2 may not pass through themotor and may be discharged through some of a plurality of such airoutlets 602 in the motor housing 60, and another part may pass throughthe motor and then may be discharged through other of the plurality ofair outlets 602 of the motor housing 60.

FIG. 4 is a view of the guide vane according to one embodiment of thepresent invention. FIG. 5 is a graph illustrating efficiency accordingto an inlet angle of a guide vane.

Referring to FIGS. 4 and 5, an inlet angle θ1 of the guide vane 330means an angle formed by an extension line extending in the direction ofa part of the guide vane 330, where air discharged through the impelleroutlet 214 makes a first contact, and the horizontal line HL.

In the embodiment, the inlet angle of the guide vane 330 may be formedsmaller than 90 degrees. That is, at least a part of the guide vane 330may be disposed to incline at a certain angle based on the vertical lineVL (which is an extension line extending in a direction parallel to anextension direction of a shaft).

Referring to FIG. 5, it may be confirmed that fan efficiency is 66.5% ormore when the inlet angle of the guide vane 330 is within a range from10 to 27 degrees. Also, the fan efficiency is maximized to be 67% ormore when the inlet angle of the guide vane 330 is 20 degrees. The fanefficiency may be reduced when the inlet angle of the guide vane 330 isless than 20 degrees or more than 20 degrees.

When the inlet angle of the guide vane 330 is less than 10 degrees, thefan efficiency drops to be 66% or less. Also in this case, it isundesirable because the guide vane 330 acts as flow resistance andincreases a flow loss of the air.

When the inlet angle of the guide vane 330 is more than 27 degrees, thefan efficiency drops to be 66% or less. In this case, the guide vane 330is substantially incapable of guiding and then the flow loss becomeslarge.

Accordingly, in the embodiment, the inlet of the guide vane 330 may beselected within the range from 10 to 27 degrees.

In the case of the prior document described above, an inlet angle of afirst guide vane is about 40 degrees. In the embodiment, the fanefficiency notably increases compared with the prior document.

A part of the second guide vane 332 may be located outside the secondflow path P2. Accordingly, the air which passes through the second flowpath P2 may be guided by the second guide vane 332.

Also, at least a part of the second guide vane 332 may increase in avertical length as getting closer to the shaft 72. In this case, an airguide area increases in the second guide vane 332 in such a way that theair may smoothly flow toward the flow guide 50.

For example, at least a part of the second guide vane 332 located in thesecond flow path P2 may increase in a vertical length as getting closerto the shaft 72. Also, at least a part of the second guide vane 332located outside the second flow path P2 may increase in a verticallength as getting closer to the shaft 72.

At least a part of the second guide vane 332 may be located at the sameheight as that of at least a part of a guide surface 501 of the flowguide 50.

In the embodiment, at least a part of the first guide vane 331 may bedisposed to incline with respect to the vertical line VL, and an inletangle of the first guide vane 331 may be selected within a range from 10to 27 degrees.

According to the embodiment, at least a part of the guide vane may bedisposed to incline with respect to the vertical line VL, and, byselecting the inlet angle of the guide vane to be within the range of 10to 27 degrees, there is an advantage of a reduced flow loss of air andincreased fan efficiency.

FIG. 6 is a bottom view of the flow guide shown in FIG. 2. FIG. 7 is aview illustrating an angle between the flow guide and a horizontal line.

Referring to FIGS. 3, 6, and 7, the flow guide 50 may include the guidesurface 501 for guiding an airflow.

The guide surface 501 may be provided on a bottom surface of the flowguide 50, and at least a part of the flow guide 50 may be formed in ashape with a diameter which is reduced as getting closer to a bottom.

The guide surface 501 may be formed of a rounded or inclined shape. Indetail, at least a part of the guide surface 501 may be formed in acurved shape curved toward the shaft 72 or may be formed with an inclineat a certain angle with respect to the horizontal line HL.

An angle θ2 of the guide surface 501 may mean an angle formed by atangent at a place of the guide surface 501 where air discharged fromthe guide vane 330 makes a first contact and the horizontal line HL.

The angle θ2 of the guide surface 501 may be smaller than 90 degrees.For example, a range of the angle θ2 of the guide surface 501 may befrom about 10 to about 30 degrees.

As the angle θ2 of the guide surface 501 increases, fan efficiency maybe increased.

However, when the inlet angle θ1 of the guide vane 330 is relativelylarge, the fan efficiency may be reduced instead as the angle θ2 of theguide surface 501 increases.

For example, when the inlet angle θ1 of the guide vane 330 is 30degrees, the fan efficiency when the angle θ2 of the guide surface 501is 0 degrees is higher than the fan efficiency when the angle θ2 of theguide surface 501 is 30 degrees.

Meanwhile, when the inlet angle θ1 of the guide vane 330 is 25 degrees,the fan efficiency when the angle θ2 of the guide surface 501 is 30degrees is similar to the fan efficiency when the angle θ2 of the guidesurface 501 is 0 degrees. That is, when the inlet angle θ1 of the guidevane 330 is 25 degrees, an effect of an angle of the guide surface 501on fan efficiency may be slight.

When the inlet angle θ1 of the guide vane 330 is 25 degrees or more, fanefficiency may be even more increased when the guide surface 501 isformed without an incline.

Accordingly, when the guide surface 501 has an angle, the inlet angle θ1of the guide vane 330 may preferably be 25 degrees or less.

When the inlet angle θ1 of the guide vane 330 is 20 degrees and theangle θ2 of the guide surface 501 is 30 degrees, the fan efficiency maybe maximized.

The air guided by the guide vane 330 may be guided toward the stator 80by the guide surface 501.

The flow guide 50 may prevent the air whose flow is guided by the guidevane 330 from flowing toward the shaft 72. That is, the flow guide 50may guide the air not to flow in a horizontal direction that isperpendicular to the extension direction of the shaft 72 and to flowdownward by changing a flow direction of the air.

The flow guide 50 may further include a coupling portion 503 provided atthe guide surface 501 and coupled with the motor bracket 40.

The coupling portion 503 may be formed as a recess in the guide surface501. The connection portion 406 may be inserted into the couplingportion 503, and the coupling portion 503 may be formed in the samenumber as that of the connection portions 406.

Accordingly, the flow guide 50 may be detachably mounted on the motorbracket 40. Accordingly, it is easy to replace the flow guide 50 andeasy to change an angle of inclination of the guide surface 501.

According to the embodiment, by selecting the angle θ2 formed by theguide surface 501 provided at the flow guide 50 and the horizontal lineto be within a range from 0 to 30 degrees, there is an advantage of aminimized flow loss of air and increased fan efficiency.

Hereinafter, efficiency due to different shapes of the vacuum suctionunit 1 and a conventional vacuum suction unit will be compared.

FIG. 8A is a cross-sectional view of a conventional vacuum suction unit,and FIG. 8B is a cross-sectional view of the vacuum suction unitaccording to one embodiment of the present invention. FIG. 9Aillustrates an airflow of the conventional vacuum suction unit, and FIG.9B illustrates an airflow of the vacuum suction unit according to oneembodiment of the present invention. A graph (a) illustrated in FIG. 10illustrates efficiency of the conventional vacuum suction unit shown inFIG. 8A, and A graph (b) illustrated in FIG. 10 illustrates efficiencyof the vacuum suction unit according to one embodiment of the presentinvention shown in FIG. 8B.

Referring to FIGS. 8A to 10, as described above, in the vacuum suctionunit 1 according to one embodiment of the present invention, the firstflow path P1 formed between the cover 10 and the guide body 310 becomesnarrower as getting closer to the guide vane 330.

On the contrary, in a conventional vacuum suction unit 2, a flow pathP1′ formed between the cover 11 and the guide body 311 has a uniformwidth. That is, an inner circumferential surface of the cover 11 of theconventional vacuum suction unit 2 does not incline and extends in ahorizontal direction.

Accordingly, a vortex of air occurs at an edge 111 of the innercircumferential surface of the cover 11 of the conventional vacuumsuction unit 2, thereby decreasing efficiency.

Referring to FIG. 10, it may be ascertained that the vacuum suction unit1 according to one embodiment of the present invention has a fanefficiency of 65.3%, and the conventional vacuum suction unit 2 has fanefficiency of 63.0%.

As described above, a decrease in efficiency may be prevented by forminga streamlined shape of an inner circumferential surface of the cover 10.

According to one embodiment of the present invention, selecting an inletangle of a first guide vane disposed on a side of a guide body to bewithin a range from 10 to 25 degrees and selecting an angle ofinclination of a guide surface of a flow guide to be within a range from10 to 30 degrees, there is an advantage of minimizing a flow loss of airand maximizing fan efficiency.

Also, by detachably attaching the flow guide to a motor bracket, thereis an advantage where the flow guide is replaceable and the angle ofinclination of the guide surface of the flow guide is easily changeable.

Also, due to the shape of an inner circumferential surface of a cover ofa vacuum suction unit being streamlined, there is an advantage ofminimizing the flow loss of air and increasing the fan efficiency.

Also, a parting line is disposed below a top end portion of a guidevane, thereby preventing a vortex or an air leakage at a portionadjacent to the parting line.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A vacuum suction unit comprising: a coverincluding an air inlet; an impeller for moving air which flows inthrough the air inlet; a motor including a stator and a shaft which isconnected to the impeller and rotates with respect to the stator; aguide device including a guide body disposed below the impeller and aguide vane provided at the guide body to guide air ejected from anoutlet of the impeller; a flow guide disposed below the guide device andguides the air guided by the guide device toward the stator; and a motorhousing accommodating the motor and comprises an air outlet, wherein aguide surface at least a part of which has a diameter reduced as gettingdownward is formed at a bottom surface of the flow guide, wherein theguide vane comprises a first guide vane which is provided on a side ofthe guide body and guides the air ejected from the impeller, and whereinan inlet angle of the first guide vane is within a range from 10 to 25degrees.
 2. The vacuum suction unit of claim 1, wherein the guide vanefurther comprises a second guide vane which is provided at a bottomsurface of the guide body, is connected to the first guide vane, andguides the air guided by the first guide vane.
 3. The vacuum suctionunit of claim 1, wherein the guide surface is formed rounded toward theshaft.
 4. The vacuum suction unit of claim 1, wherein an angle ofinclination of the guide surface is from 10 to 30 degrees.
 5. The vacuumsuction unit of claim 1, wherein an inner circumferential surface of thecover is formed in a shape which inclines at a certain angle withrespect to a top surface of the guide body.
 6. The vacuum suction unitof claim 1, wherein a first flow path is formed between an innercircumferential surface of the cover and the guide body, and the firstflow path becomes narrower as getting from the outlet of the impellercloser to a top end portion of the guide vane.
 7. The vacuum suctionunit of claim 6, further comprising a motor bracket disposed below theguide device and coupled with the cover, wherein a second flow pathconnected to the first flow path is formed between an innercircumferential surface of the motor bracket and the guide body.
 8. Thevacuum suction unit of claim 7, wherein the cover comprises a firstcoupling portion coupled with the motor bracket, and the motor bracketcomprises a bracket body for forming the second flow path and a secondcoupling portion provided outside the bracket body and connected withthe first coupling portion.
 9. The vacuum suction unit of claim 8,wherein a bottom surface of the first coupling portion is located lowerthan the top end portion of the guide vane.
 10. The vacuum suction unitof claim 7, wherein the flow guide is detachably coupled with the motorbracket, and the flow guide comprises a coupling portion connected tothe motor bracket.